Particularly in the context of mobile devices, it is desirable to provide location awareness capabilities. An expanding variety of technologies have been developed to provide a device with information about its location, allowing it to selectively deliver information based on its location context or to otherwise adapt its operation. Common examples include navigation aids that may be used to guide a user to a desired destination, social networking applications that may inform the user about others that may be in proximity, targeted advertising schemes that may provide information relative to the user's location or tracking utilities that may provide real time information about a user's whereabouts.
In some cases, a mobile device may have position determination capabilities in the form of a Global Positioning Satellite (GPS) system that, under the proper conditions, may provide precise information about the geographic location of the device. However, GPS performance may be subject to degradation when visibility of the satellites is reduced. For example, use of GPS in an indoor environment may lengthen the time needed to obtain the necessary fix on the satellites or may prevent it entirely. Alternative means for determining the position of a mobile device that are more amenable to indoor applications may include wireless local area network (WLAN) ranging, positioning based on cellular reception, dead reckoning techniques and others. However, these alternate means may not offer the same precision as available through GPS systems. Accordingly, there is a need for systems and methods to refine location determinations to improve accuracy or otherwise augment position information regarding a mobile device that may be used indoors as well as outdoors.
Furthermore, not all mobile devices may be equipped with GPS systems, yet such devices may still benefit from accurate location awareness. Still further, despite the precision offered by GPS systems, it may still be desirable to provide additional sources of position information to improve GPS performance, such as by enhancing heading information or decreasing the time to first fix. As such it would be desirable to refine position determinations, regardless of the technique used.
This disclosure satisfies these and other needs as described in the following materials.